SB 253: 5 Steps to Go From Zero to Filed

The Core Problem: A Reset Deadline, a Shrinking Runway

CARB moved the Scope 1 and 2 reporting deadline from August 10 to November 10, 2026, and confirmed a phased approach to Scope 3 starting in 2027. Many sustainability and compliance teams paused their SB 253 prep waiting for exactly this kind of clarity, and now have roughly 15 weeks left to get a defensible filing done. Treating this as a scramble is a real risk. Treating it as a fixed, structured path is the way through.

A Structured Path, Not a Sprint

Spreadsheets and from-scratch platform builds both fall short of the November 10 deadline: one was never built to survive assurance, the other typically takes six months or more. This guide walks through Novisto's 8-week, 5-phase path in full, phase by phase, with the milestone, what happens, and what your team needs to provide at each stage, so you know exactly what the next 8 weeks look like before you commit to them.

Building Toward 2027, Not Just November 10

Filing on November 10 is a checkpoint, not a finish line. The guide covers what CARB requires for Scope 3 and limited assurance starting in 2027 and 2028, and how the data, methodology, and documentation built for this filing carry forward, instead of requiring a second sprint from zero next year.